Unintended Consequences of not Specifying Exclusionary Illnesses for Systemic Exertion Intolerance Disease.
Jason, Leonard A, Sunnquist, Madison, Kot, Bobby et al. · Diagnostics (Basel, Switzerland) · 2015 · DOI
Quick Summary
Researchers studied a new proposed name and definition for ME/CFS called SEID (Systemic Exertion Intolerance Disease). They found that the new definition was much looser than the old one and incorrectly labeled people with depression and other illnesses as having SEID when they didn't actually have ME/CFS. This means the new definition could overestimate how many people have ME/CFS.
Why It Matters
This study is critical because diagnostic criteria directly impact who receives a diagnosis and what treatments they pursue. If ME/CFS criteria are too broad, patients with other treatable conditions like depression may be misdiagnosed, delaying appropriate treatment. Accurate criteria also ensure research enrolls the right populations, making study findings more meaningful for actual ME/CFS patients.
Observed Findings
- Prevalence of positive cases increased 2.8-fold when applying SEID criteria versus Fukuda CFS criteria in a community sample (0.42% to 1.18%)
- Substantial numbers of individuals with major depressive disorder met SEID criteria but would not have met Fukuda CFS criteria
- Patients with various other medical illnesses were reclassified as SEID-positive under the new criteria
- The SEID criteria lack clear exclusionary illness specifications that were present in the Fukuda definition
Inferred Conclusions
- The removal of exclusionary illnesses from the SEID definition resulted in significant overdiagnosis and misidentification of non-ME/CFS populations
- Diagnostic criteria refinement is necessary to maintain specificity and prevent misclassification of other illnesses as SEID
- Exclusionary illness specifications serve an important function in preventing diagnostic confusion with psychiatric and other medical conditions
Remaining Questions
- What is the optimal balance between sensitivity and specificity for ME/CFS diagnostic criteria?
- How should exclusionary illnesses be specified to accurately distinguish ME/CFS from comorbid depression and other medical conditions?
- Would revised SEID criteria with reintroduced exclusions improve diagnostic accuracy without missing true ME/CFS cases?
What This Study Does Not Prove
This study does not prove that the SEID criteria are definitively wrong or should never be used—it identifies a problem that requires further refinement. It also does not establish whether removing exclusions might capture previously undiagnosed ME/CFS cases; it only shows that other illnesses are being captured as well. The study is observational and cannot determine the optimal balance between sensitivity and specificity.
Tags
Symptom:Fatigue
Method Flag:Weak Case DefinitionExploratory OnlyMixed Cohort